On mean field homogenization schemes for short fiber reinforced composites: Unified formulation, application and benchmark

[摘要] This paper revisits the topic of mean field homogenization for short fiber reinforced composite materials. A short glass fiber reinforced thermoplastic polyamide 6.6 with a fiber mass fraction of 35 % is used as an example material for which microstructural analyses and experimental tests were performed. We cover a set of common models: the Self-Consistent (SC), Mori-Tanaka (MT), Ponte Castaneda-Willis (PCW), Interaction Direct Derivative (IDD) and Two-Step (TS) schemes. We first recast them into a unified formu-lation that permits a thorough theoretical comparison, including the topics of loss of major symmetry as well as connections between the models. We are able to show that the MT, PCW and IDD schemes can be expressed in a surprisingly similar form. This extends to the equations for prediction of effective stiffness and compliance tensors as well as the strain and stress localization tensors. Secondly, we address the res-olution of the material microstructure within mean field homogenization schemes, comparing classical and more recent and efficient methods. Last, we benchmark the different mean field schemes and mod-eling approaches, including comparisons to numerical homogenization by Fast Fourier Transformation (FFT) and experimental data from tensile tests. These show that the MT and TS schemes are both capable of accurately modeling the composite material for complex orientations and homogeneous fiber phases. For possibly inhomogeneous fiber phases only the TS scheme yields both accurate and physically reason-able results. Other models such as the IDD or PCW are of great theoretical importance, but cannot be gen-erally applied for the given material class. (c) 2021 Elsevier Ltd. All rights reserved.

[发布日期] 2021-11-01

[关键词] Short fiber reinforced composites;Short glass fiber reinforced thermoplastics;Polyamide 6;6;Mean field homogenization;Micromechanics;Stress localization;FFT